Brushless direct current (BLDC) motors are used in many different applications that primarily involve continuous revolution of a motor shaft. For example, a BLDC motor may be used to rotate a data disc at a constant angular velocity. In contrast, stepper motors are often used to make controlled incremental rotations of a motor shaft, which often include relatively frequent pauses or stoppages between the movements. For example, a stepper motor may cause movement of a laser used to read data from the data disc. However, a stepper motor may be controlled to provide extended revolution of the motor shaft, and thus operate similar to a BLDC motor. A controller may cause outputs of variable current to the coils of the stepper motor to provide extended revolution of the motor shaft.
Sometimes, operation of a motor shaft is hindered by user interaction with the motor shaft or user interaction with a part coupled to the motor shaft. For example, a user may desire to move a part that is under control of a motor. Unlike BLDC motors, stepper motors may accommodate user interaction without at least some of the adverse effects experienced by the BLDC motors, such as heat generation and/or damage to the coils of the motor when the user interaction applies a force against a controlled rotation of the motor.